The invention relates to a control system and method for a high production pump which pumps viscous materials such as plaster, slurry, and fireproofing materials. Recent improvements in this type of pump has resulted in higher production, particularly in pumping fireproof materials. One is Monokote brand material manufactured by W. R. Grace company. Generally, these materials are a cementitious (plaster) material which require the addition of water at the job site. These materials include 90-96% gypsum binder and aggregate with fiberglass, filters, and air entraining agents. The materials are highly spongy in a pumping state. Due to their nature, these materials may cause damage if pressures are not accurately controlled. Rupture of supply lines can occur if the pump remains on while the manual nozzle is closed creating high supply line pressures. With current improvements, production may be high enough to supply a pair of nozzles instead of one. This is usually done through a "Y"-branch. If one nozzle is cut off, the pressure will be too high in the remaining line. Supply line rupture may result. Another disadvantage of poor pressure regulation is material composition breakdown.
The invention has application to pumps generally of the type manufactured by the Essick Manufacturing Company of Charleston, South Carolina, model TM30, with improvements made for high production. Other typical plaster pumps are disclosed in U.S. Pat. Nos. 4,521,163, 2,432,671, and 2,146,709.
While there are control systems for dispensing fluids at regulated pressures or volumes, they have not been applicable or entirely suitable to controlling high production pumps which pump plaster and the like viscous materials. For example, see the current control systems in U.S. Pat. Nos. 4,442,953 and 3,997,080. Patent Nos. 3,885,739 and 1,953,393 disclose nozzles for dispensing fluid material with electrical switch controls at the nozzle. The later patent shows a pump turned on by a manual switch at the handle.
Accordingly, an object of the invention is to provide a control system and method for a high production plaster pump.
Another object of the invention is to provide a control system method for a high production pump which pumps plaster and other viscous materials which automatically protects against overpressures in the pumping system.
Another object of the invention is to provide a control system and method for a high production pump having plural dispensing nozzles wherein pressure is automatically regulated should one of the nozzles be closed.
Another object of the invention is to provide a control system and method for a high production plaster pump which controls pressure of the plaster or other viscous material in a manner that break down of the material does not occur.